Have biologists found the anti-aging secret?

So, there's good news and bad news coming out of the scientific community this week.

Biologists might have finally found the secret to fighting off aging, at least in mice. The bad news? That secret is literally the blood of the young.

Three studies will be published this week in the journals Science and Nature, each exploring the regenerative properties of young blood.

Two teams at Harvard and one at Stanford found that a shot of younger blood can produce dramatic improvements in older mice.

The studies are based on decades-old research which infused old mice with the blood of younger mice by literally stitching the animals together. The process is called parabiosis.

Parabiosis turned out to be beneficial for the older mice, and a Stanford team under Dr. Tony Wyss-Corey decided to investigate why. The team used direct injections of plasma to infuse old mice with young blood.

The transfused mice were then run through a series of standard lab tests designed to measure brain functions. The researchers found old mice with younger blood did better than their peers on learning and memory tests.

Interestingly, the improvements seen in the transfused mice vanished if the plasma was heated first - suggesting proteins in the plasma might be responsible for the change. Wyss-Corey said he hopes to pin down what makes young blood so beneficial to old mice in future studies.

And before you get any funny ideas, he told NBC "You can't drink the blood. ... If you wanted to try that in humans you'd have to get a transfusion. And you can't just do that at home."

Over at Harvard, two separate teams lead by Dr. Amy Wagers and Dr. Lee Rubin conducted similar blood-swapping experiments. The teams injected old mice with the protein GDF11, which is more prominent in young mouse blood and has been shown to reverse the signs of aging in the heart.

Turns out, GDF11 can also help out brain, skeleton and muscle tissue as well. According to The Guardian Wagers' team noted improved muscle function and repair, while Rubin's team found transfused mice had more activity and better blood flow in the brain.

Oh, and GDF11 is found in humans as well as mice. Wagers and Rubin say they expect to have human clinical trials of the protein's effects in three to five years.

One independent genetics scientist told National Geographic that taken together, the trio of studies is nothing short of game-changing.

"The changes are astounding in terms of rejuvenating the mice. ... I'm kind of blown away, really, by the results."

And the head of an aging research non-profit group told USA Today the findings couldn't have come soon enough.

"We need to get about funding this research for human use in time to meet the tsunami of age-related diseases that are headed our way."

The Stanford study was published in the journal Nature Sunday, and both Harvard studies will be published in the journal Science on Friday.